The first bans weapons by name, such as the original Colt AR-15. The second covers the popular AK and AR-15 rifle platforms, which include a host of similar guns made by different manufacturers. And the third includes guns that feature generic characteristics, such as pistol grips and telescoping stocks, which are largely cosmetic.

A "detachable magazine" which means any ammunition feeding device that can be removed readily from the firearm with neither disassembly of the firearm action nor use of a tool being required. A bullet or ammunition cartridge is considered a tool. Ammunition feeding device includes any belted or linked ammunition, but does not include clips, en bloc clips, or stripper clips that load cartridges into the magazine.

A "flash suppressor" which means any device designed, intended, or that functions to perceptibly reduce or redirect muzzle flash from the shooter's field of vision.

A "forward pistol grip" which means a grip that allows for a pistol style grasp forward of the trigger.

A "pistol grip that protrudes conspicuously beneath the action of the weapon" means a grip that allows for a pistol style grasp in which the web of the trigger hand (between the thumb and index finger) can be placed below the top of the exposed portion of the trigger while firing.

A "thumbhole stock" which means a stock with a hole that allows the thumb of the trigger hand to penetrate into or through the stock while firing.

The law was upheld in 1999 via the Kasler v. Lockyer decision. A 2001 decision — Harrott v. Kings County — altered that decision slightly. It required the department of justice to determine which specific makes and models of AR-style and AK-syle weapons are prohibited.

Are there loopholes?

Bullet buttons can render the law basically useless. As described by the Daily Beast: "a rifle is not an assault weapon if it has a fixed magazine" as opposed to a detachable magazine. A fixed magazine means it can't be removed without dissembling a portion of the firearm or without using a "tool." Soon firearms started to feature a button that could release a magazine by pushing it with the tip of a bullet, which was deemed a non-tool.